Domestic appliance



Dec. 19, 1961 w. G. PONTIS 3,013,736

DOMESTIC APPLIANCE Filed Feb. 26, 1958 5 Sheets-Sheet l INVENTOR.

HIS ATTORNEY l Dec. 19, 1961 w. G PONTIS DOMESTIC APPLIANCE 3Sheets-Sheet 2 Filed Feb. 26, 1958 INVENTOR.

Mil/1am 6'. Hmzis BY 5 z 6 H15 ATTORNEY 19, 1961 w. G. PONTIS DOMESTICAPPLIANCE 3 Sheets-Sheet 5 Filed Feb. 26, 1958 [Mi/liar Fom is BY HISATTORNEY United States Patent Oflflce Delaware Filed Feb. 26, 1958, Ser.No. 717,623 7 Claims. (Cl. 241-46) This invention relates to a domesticappliance and more particularly to apparatus for comminuting waste in animproved manner to produce a flowable mixture suitable for discharge tothe drain-line of a sink.

In particular, this device relates to apparatus for attachment to theoutlet of a sink and having a power driven impeller for initiating thecomminuting shredding and abrading of waste material placed within thedevice.

A particular object of this invention is the provision of an improvedcomminuting device which incorporates a difierential obstacle bypass toaid an unloading escapement through a clearance in the open center of animpeller, for particles tending to wedge or jam.

A further object of this invention is the novel configuration of animpeller cutting tooth wherein a curvature in the direction of impellerrotation effects a raking action at the cutting end of the tooth and,through a progressively increasing rake action, a jam-preventingunloading func tion at the inner end of the tooth.

A further advantage of the improved waste disposer results in acontrolled rate of comminution proceeding downwardly past a series ofselectively placed stationary pins, a series of peripherally arrangedcutter ports and a bottom row of open-slotted fibre cuting slots.

It is also an object of this invention to provide a lubrication systemfor vertically mounted motors wherein the oil system is permanentlysealed and wherein liquid separation of bearing surfaces for long-lifeoperation is accomplished without the need of anti-friction bearings,such as balls, rollers, etc.

A further object is the provision of an improved stationary cutterliner.-

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings:

FIGURE 1 is a side sectional elevation of a food Waste disposerembodying the invention;

FIGURE 2 is a sectional view taken along line 2-2 of FIGURE 1 andshowing the relation of impeller cutter to the cutter liner pins;

FIGURE 3 is a sectional view taken along line 33 of FIGURE 1 showing therelationship between a lower portion of the impeller cutter and theoutflow cutter ports of the cutter liner;

FIGURE 4 is an elevational view taken along line 4-4 of FIGURE 3 andshowing the relationship of the peripheral shearing teeth on theimpeller with the bottom shearing edges of the outflow cutter ports;

FIGURE 5 is a plan view of the cutter impeller;

FIGURE 6 is a fragmentary sectional view taken along line 6-6 of FIGURE5 and showing the rotary sweep device for removing comminuted waste fromsaid disposer;

FIGURE 7 is a seectional view taken along line 77 of FIGURE 1 showingthe waste disposer sink mounting means;

FIGURE 8 is a sectional view taken along line -8--8 of FIGURE 1 andshowing the novel lubrication sealing arrangement of this invention;

FIGURE 9 is a fragmentary sectional view similar to FIGURE 8 and showinganother lubrication arrangement;

FIGURE 10 is a sectional view taken along line 10-10 of FIGURE 4 showingan inserted cutter liner pin;

0 FIGURE 11 is a view taken along line 10 10 of FIG- URE 4 showing anextruded cutter liner pin; and

FIGURE 12 is a plan view taken along line 1212 of FIGURE 9 to illustratethe centrifugally actuated oil grooves.

In accordance with this invention as depicted in FIG. 1, a disposershown generally at 10 is supported in hanging relation from an outletcollar 12 on a waste or water receiving container or sink 14. Disposer10 is comprised of a mounting assembly 16, and a comminuting chamber orhopper 18 having a volute pumping area 20 to which a drainage outlet 22connects. A rubber or resilient insert 24 is formed with a flexibleannular rib 26 and a rib 28 reinforced by ring 30 to eflect anunyielding stable diameter for rib 28. A valley is formed between theannular ribs 26 and 28 to receive a radially inwardly directed collarflange 32 of the sink outlet collar 12. The bottom of the cup-shapedresilient member 24 is segmented by radially slitting at 34 to formyielding tabs 36. The cupshaped member 24 may be removably installed inthe sink outlet 12 by forcing it downwardly. The rib 26 will yield topass inwardly extending rib 32 and it will expand again thereafter intoliquid sealing engagement with an inwardly projecting annular housingflange 38. When in place,

the cup member 24 forms a waste inlet 40 having an upper shoulder 42. Astopper 44 carries four support tabs 46 which bear against the verticalsides of inlet 40 to hold the stopper 44 in either a raised liquidpassing relationship or a lowered stopping relationship to the outletopening 40. When raised, water may flow between the tabs 46, through theopening 40 and 33 into the comminuting chamber 18. The rubber tabs 36will yield to pass larger waste particles. An adapter knockout plate mayalso be provided at 48 in the side of the comminuting chamber 18 forattachment of a dishwasher or the like.

The novel method of attachment of a comminuting chamber 18 to thedepending outlet sink flange 12 will now best be understood withreference to FIGS. 1 and 7 wherein a simply connected, substantiallyvibrationless interconnection exists between the sink 14 and thedisposer 10. A unitary mounting assembly 16 is comprised of a topsupport ring 50, a bottom support ring 52 and annular rubber rings orbushings 54 and 56. The bushing 54 carries a depending portion 58 whichcarries ports 60 to receive three adjusting bolts 62 and the mountingassembly securing rivets 64. Similar ports 65 are provided in bushing 56and are placed in matched relation to the ports 60 of bushing 54. Thedepending portion 58 of bushing '54 forms an annular recess 66 whichreceives a radially inwardly projecting flange 68 of a dependingdisposer support collar 70. The mounting assembly'is thus supported inassembled relation by the three rivets 64 which are isolated fromsupport flange 70 by the rubber bushings 54 and 56. The support collar70 is further segregated from annular support ring 52 by a dependingannular flange 72 of bushing 56. A plurality of adjusting bolts 62 arethreaded in upper support ring 50 and lower support ring 52 and adaptedto extend downwardly below the lower support ring 52 for subsequentadjustmeent of the disposer 10 to the sink opening 12. The bolts 62 aresimilarly isolated by bushings 54 and 56 from the vibrating portions ofthe disposer. The inwardly projecting flange 68 of support collar 70 isformed with recesses 74 large enough to receive the bolts 62 and rivets64 without touching collar 70. In attaching the mounting assembly 16 tothe depending sink outlet collar .12,

a splitring 76 having apertures 78 to receive the bolts" 62 and rivets64 is placed with its annular ledge 80 in relationship to the dependingcollar flange 32. The bolts 62 wardly against the split ring 76 which isstopped by flange Patented Dec. 19, 1961 32. The mounting assembly isthereby securely attached to the sink but carries the disposer supportcollar 70 in rubber isolated relationship to the depending sink outlet12.

The comminuting chamber or hopper 18 is formed with an inner recess 82for receiving a hopper cutter liner 84. The recess 82 is cast with aone-half degree taper having a narrowest diameter at the upper portionof the recess 82. A similar one-half degree taper in complementaryrelationship to the taper of recess 82 is fabricated into the hoppercutter liner 84. The liner 84 may then be shrunk-fit into the recess 82.Another method of securing the cutter liner to the housing 18 is througha thermosetting cement which bonds the liner to the housing. Since thecutter liner 84 is heat treated to give the cutting surface (describedhereinafter) a hardness of 55 to 60 Rockwell, it is desirable to resisttemperatures in assembling the cutter liner to the casing 18 which wouldanneal the temper from these cutting edges or surfaces. One method ofshrinkfitting prescribes heating the hopper casing 13 by a localizedelectrical field to expand the casing in the area of recess 82. Thecutter liner 84 is dropped into the expanded recess 82 which thenshrinks upon cooling into a snug hopper liner retaining capacity. Wherethe cutter liner 84 is formed of a comparatively soft metal utilizedsolely to support a plurality of spaced cutting pins, described morefully hereinafter, the cutter liner 84 may be firmly held to the casing18 by performing a die casting operation of the hopper casing 18 aboutthe cutter liner, supported on the die cast mold core.

The novel, descending, progressive comminuting procedures of thisinvention will now be more fully described with reference to FIGS. 1, 2,3 and 4. The cutting assembly is comprised principally of the hoppermounted cutter liner 84 and a rotating impeller cutter 86 cooperating ina comminution process with the liner 84. The progressive downwardcomminuting action is facilitated by a plurality of pins, showngenerally at 88, formed in concentric circles about the innercircumference of the cutter liner 84. The pins 88 are approximately /sin diameter and arranged in twelve circles containing six pins each, onecircle above the other. The circles of pins are so disposed that theplane defined by the top of one circle of pins coincides with the planedefined by the bottom of the pin circle immediately thereabove. Forinstance, the top of pin 88a is in the same plane as the bottom of pin8812. Along the bottommost edge of cutter liner 84 a series ofinverted-U outflow cutter ports 90 are cast in the liner, the open draftoutflow ports permitting free do\vnflo\v. The outflow cutter ports 90are arranged about the periphery of the liner 84 in a single plane andare formed with a bottom cutting or shearing edge 92. Where the cutterliner 84 is formed in a shell casting process the cutter pins 88 aremachined to form a hard cutting edge about the periphery of a topsurface 94. A fine grinding or machining process similarly creates aninside peripheral cutting edge on the outflow cutter ports 90. Afabricating procedure has also been used in forming the cutter liner 84,as best seen in FIGS. and 11. In the arrangement of FIG. 10 tungstencarbide cutter pins 96 are inserted into a relatively soft stainlesssteel liner 98. This is accomplished by means of an automatic operationin which the cutter pin insert becomes its own piercing punch, employingthe automatic magazine-equipped punch press for forcing the cutter pins96 through the liner wall until the pin 96 bottoms on the exterior wall100 of the liner 98. The pins 96 are tapered so that a tight fit isaccomplished when the pins are forced into place in the liner wall. Anextrusion process (FIG. 11) has also been used to form the cutting pins88. In this process the pins 88 are machined to give a sharp-edge topsurface 94, as described in connection with the shell casting processhereinabove. In both of the latter two fabricating operations thecompleted cylindrical hopper liner 84 is formed by wrapping the pincarrying liner element to form a cylinder and welding the resultantabutting seam. Where the insert pin process depicted in FIG. 10 is used,the completed liner may be secured to the disposer casing 18 inconjunction with the die casting of this casing. Since only the pins 96are hardened, the heat generated in the die casting operation will notanneal the pins. In positioning the cutter liner 84 in hopper casing 18the liner is so disposed to place the uppermost point of the outflowcutter ports in juxtaposition with the top wall 102 of the peripheralflange cavity formed at the bottom of casing 18.

Reference may now be had to FIG. 5 for a more com plete understanding ofthe configuration of the impeller cutter 86. The impeller cutter isformed in a shell casting process wherein a curved cutter tooth 104 anda differential straight cutter tooth 106 is formed on the upper conicalimpeller surface 108. At spaced positions upon the bottom of theimpeller 86 two identical rotary dynamic proximity sweep devices 110 areformed. The sweep devices 110 are formed with a radially inwarddepending rib 112 which projects tangentially from the hub 114 of theimpeller 86. The ribs 112 terminate in an end portion 116 which extendsbeyond the outer peripheral edge of the impeller disc 86. With theimpeller 86 rotating in the direction of the arrow (FIG. 5) the sweepdevices 110 create a pumping action which sweeps any comminuted materialfrom the disposer. Formed in the outer peripheral edge of the impellerdisc 86 are perimeter clearance gristle cleaning cutters 118. Althoughfour teeth are shown on opposite sides of the impeller disc in FIG. 5,it has been found that one tooth provides satisfactory shearing for thefibrous material produced during comminution.

A particular feature of this invention is the provision of aspecifically designed curvature for the curved or rake cutter tooth 104.The tooth 104 is so designed to define an innermost escape section 122and an outermost rake section 124. For domestic food waste disposal, thecurvature of cutter tooth 104 should be such that a line 123 drawntangent to the outer peripheral edge of the tooth rake section 124 formsan angle A with a line drawn radially from axis zero of disc 86 to theleading edge 126 of the rake section. Similarly, the design soconfigures the escape section 122 that a line 125 drawn tangent to theescape edge 128 forms an angle B with a radial line drawn to edge 128.Careful calibration of the curvature for tooth 104 has shown anacceptable range for angle A of 10-30 and a range for angle B" of 30-50.However, the most efficient comminuting action is found to exist whenthe leading rake angle A is 20 and the trailing escape angle B is 40".The radius of curvature for tooth 104 has been found most effective as10 /2" taken from the point 126 along a line 127 20 radially inwardlyfrom a tangent 130 drawn to the outer periphery of the cutter impellerdisc 86 at the outer leading edge 126 of curved cutter tooth 104. Thesignificance of the specifically designed configuration is found in thecooperation of cutter tooth 104 with the cutter liner 84. The rakesection 124 is so disposed to resist any attempt on the part of anygiven waste particle to impale, wedge or jam against the cutter pins 88.The receding rake angle forces the Waste away from the wall, which isthen either impelled back toward the cutter liner by the reversecurvature of the escape section 122 or allowed to escape through theopening C to the opposite side of the comminuting chamber. Thecentrifugal force generated by the rotation of cutter disc 86 provides acontinuous urging of the waste material toward the cutting surfaces ofthe periphery of the comminuting chamber 18.

A straight tooth 106 is formed on the upper surface 108 of the impeller86 diametrically opposite curved tooth 104. The rake angle which tooth106 defines in relation to cutter liner 84 is the same as the angleformed by the rake section 124. The tooth 106 provides a differentialcutting action in that its configuration is straight as compared tocurved tooth 104 and its length is shorter. Thus,

it should be understood that the center escape opening C between thediametrically opposite cutter teeth is functional when used with acurved cutter tooth, i.e. stalling of the impeller 86 is minimized. Asin the case of the curved blade, the small rake angle at the cutting endof the differential cutter tooth 106 is effective on the smallest wasteparticle in eliminating a wedging, jamming, stalling condition.

In elevation (FIG. 1), curved cutter tooth 104 and the differentialcutter tooth 106 are seen to have identical configurations for theirradially outer edges which are significant to provide the progressivelyfiner downward comminuting action utilized so effectively in thisinvention. The cutter teeth 104, 106 both have an upper tapered portion132 which cooperates with the lower circles of pins 88. A lower toothcutting section 134 provides the sharp edge which, in conjunction withthe outflow cutter ports 90, completes the comminution of the wasteparticles. The most effective taper for the upper portion 132 of cutterteeth 104, 106 has been found to be 1 /z in the direction indicated byFIG. 1. The turntable or upper surface 108 of impeller disc 86 isconically formed with an approximate 5 taper downward from the centeraxis of the impeller, as best seen in crosssection in FIG. 1.

As aforesaid, a rotary sweep device 110 is formed on the bottom of theimpeller disc 86. As an aid in the clearance action, the sweep devicehas its lower edge 136 formed at the same angle as the top conicalsurface of the impeller disc, i.e. 5 downward taper from the impellercenter toward the outer periphery. This downward taper places the sweepdevice 110 in close proximity to the outer limits of the outflow chamberto more eifectively sweep the comminuted waste material from thedisposer (FIG. 6). The impeller mounting arrangement in conjunction withthe motor housing will now be disclosed with reference to FIG. 1. Theimpeller disc 86 is tapped at 138 to receive a threaded end portion of amotor shaft 140. The motor housing is formed with a lower prime moversection 142 and an upper section 144 in which resides a novel shaftlubricating'system shown generally at 146. The upper motor section 144is cast with its top so configured to cooperate with the comminutingchamber casing 18 to form the bottom half of a pump housing. Inparticular, a depressed sweep cavity 148 is formed with the same taperdescribed in connection with the top surface 108 of the impeller disc 86and the bottom edge of the sweep device 136. The outermost peripheralportion 150 of the cavity 148 is formed in volute fashion to slopeslowly downwardly about the outer peripheral portion of the pump cavity150 to a lowermost trough section 152 where it connects to drain outlet22. In this regard, and with reference to 'FIGS. 1 and 6, the pump-outor sweep-out is seen actuated by the rotary motion of the sweep device110. In view of its close proximity to the defining limits of the pumpchamber the sweep device centrifugally urges. the fluid waste to theouter peripheral portion 150 of the pump chamber. As it is swept towardthe lowermost portion of the descending peripheral trough 152, it isimpelled through the outlet 22 to drain.

An effective lubrication system has been devised for the disposer ofthis invention in which a life-time lubrication is provided. The uppermotor section 144 is formed with a centrally located collar 154 havingan upper annular recess 156 and a lower annular ledge 158. The impellerdisc 86 defines a liquid sealing shoulder 160 and a thrust bearingsurface 162. The depending collar portion 154 is formed with severalradial support ribs 164 east integral therewith. At the radially innerend of the ribs 164 and integral therewith a shaft bearing cylinder 166is disposed in support relationship to motor shaft 140. Carried in thesupport cylinder 166 is a bearing metal liner 168 to provide the bearingsurface in which the shaft 140 rotates. This liner has an uppermosthorizontal thrust support flange 170 (FIG. 12) in which oil grooves 172are formed tangentially to the shaft receiving aperture 174. It isimportant to note that the bearing metal liner 168 is non-porous and inthis regard may be eliminated by a preferred and simplified alternativearrangement seen more clearly in FIGURE 9. In this arrangement a portionof the casting 144 is formed to provide a bearing support cylinder 176supported as in the above described arrangement by ribs 164. The FIG. 1lubrication chamber 178 defined at its outer periphery by casting collar154 is sealed closed at its bottom by an oil-tight seal arrangement 180secured by an O ring 182 to the collar 154 and by crimping the lowerannular edge portion of 154 over washer 184. The top of thelubricationcavity 178 carries an annular seal 186 secured to castingrecess 156 by a snap ring 188. A Bellville washer 1% acts upon theradially inner end of seal 186 to force a carbon bearing ring 192 intooil-egress preventing, water-ingress eliminating engagement withshoulder of impeller disc 86. A pressure relief opening 194 is providedat one point in the annular seal ring 186 to guard against pressurebuildup within the lubricating chamber 178.

The lubrication system utilizes centrifugally actuated oil circulationto lubricate the motor shaft 140. With the impeller disc 86 rotating ina clockwise direction (FIGURE 12), the relative movement betweenimpeller shoulder 162 and bearing liner flange sets up a camming actionwhich urges oil between the liner and the shaft into oil grooves 172.The relative rotational movement then initiates centrifugal forces inthe oil grooves 172 thereby to throw any oil within the grooves radiallyoutwardly. As oil is moved outwardly from the grooves, additional oil isdrawn between the shaft 148 and liner 168 as a replacement therefor; Inthis manner, it may therefore be seen that an oil circulation is set upfrom the reserve cavity 178 inwardly at the bottom of bearing liner 168to lubricate the shaft 140. Since the lubrication system is sealed, thelubricant is ageless and a permanent lifetime system is effected.Although oil alone will function effectively as a lubricating vehicle, afibrous wicking. comprised of 85% oil is particularly satisfactory.

A similar circulation, as seen by the arrows, is introduced in thelubrication arrangement of FIGURE 9. This embodiment has been furthersimplified by sealing the top of the lubricant chamber 178 by a singleresilient seal 196 which seals against water ingress at 198 and vagainst oil egress, at 200.

In assembling the impeller motor section 141 to the comminuting chamber18, an upstanding tenon 202 .00- operates with a mortice 204 and agasket 206 to effect a tight liquid sealing engagement at the jointure.A snap ring 288 overlies a peripheral flange on both the impeller motorassembly 141 and the comminuting section 18 to securely retain the twoin assembled relationship. To assemble the disposer 10 to the sink 14,an upper recessed flange 210 is placed in underlying relationship withthe depending support flange 70 of sink mounting assembly 16. Thedisposer is rotated until the apertures 212 are in line with the chamberconnecting openings 214 and the connecting bolts 216 inserted. Thedisposer 10 now depends in a rigid though relatively vibrationlessconnec-' tion with the sink outlet flange 12.

The novel progressive comminuting action prowded by this invention willnow be described with reference to FIGURE 1, 2, 3 and 4. The loading cap44 is lifted to provide access for any bulk or waste desired to becomminuted. The tabs 36 yield to pass any material which will not flowthrough inlet cup opening 33. With the waste material in the hopper orchamber 18, water is introduced to the chamber and the motor 142 isenergized to initiate the comminuting or grinding process. As fooddescends in the hopper 18, it meets first the upper circles of cutterpins 88. A progressive snagging action. occurs which breaks off orsubdivides the larger waste particles whereby the leading edge of thepin cutting surface 94 snags into the waste. This snagging or shearingaction increases as the full diameter of the pin proceeds through thewaste material. The progressively larger cut of the pins 88 permits useof a smaller motor 142 than if the pins presented a straight frontalcutting surface. A second stage in the comminution occurs when the wastereaches a position adjacent the top of cutter teeth 104, 106 (FIGURE 2).At this point, the tolerance between the upper portion of tapered toothsegment 132 is greatest. As the waste is introduced to lower portions oftapered segment 132 (FIGURE 3), the cut becomes finer as the cutterteeth 104, 106 cooperate with the progressively lower circles of pins,i.e. those circles in which pins 218, 220, 222 and 224 lay. As the wastesettles in the chamber 18, the conical configuration of the turntable ofimpeller disc 86 provides a third stage of progressive comminutionwherein the reduced particles are acted upon by lower tooth segment 134which cooperates with the outflow cutter ports 90 in effecting athorough, complete comminution. In the comminution of many fibrousmaterials such as gristle and husks, long fibers or strings aregenerated which become jammed between the rotating impeller 36 and thecutter liner 84. For this reason, a fourth comminuting stage is requiredto shear or sever the lengths of fiber which would tend to jam and stallthe disposer. FIGURE 3 is most illustrative of the shearing rotatingimpeller teeth 118 in which a leading cutting edge 226 moves relativelyto a bottom shearing edge 92 of outflow cutter port 90 in extremelyclose proximity thereto. This action serves to reduce the lengths to afineness which will eliminate any jamming which such tangled fiberscould produce. The combined result is a freely fiowable substance.

In the reduction process provided by the four stages outlinedhercinabove, the waste is comminuted in a rapid manner to a finenesswhich is washed through the outflow cutter ports 90 into the wasteremoval chamber 20. The rapidly rotating sweep device arms 112 impel theWaste and water to the outer peripheral trough of the pump housing. Therapid pumping action induces a centrifugal force to the fluid wastewhich carries it around the descending trough 152 to the outlet 22 whereit is propelled quickly and positively into the sewage system.

Although the comminuting action provided by the above described deviceis both efiicient and rapid, the shock absorbing mounting arrangementprevents a transmittal of vibration noises to the sink. The fineness ofgrind and the outlet force of the rotary dynamic sweep device combine toprevent clogging of the sewage system.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, as may come within the scope of the claims whichfollow.

What is claimed is as follows:

1. A food waste disposer comprising a comminution chamber; means forconnecting said chamber to the drainage outlet of a receptacle for foodwaste and water; a cutter liner disposed in said chamber, said cutterliner having radially inwardly directed shredding pins in independentspaced planar relation and outflow cutter ports; said outflow cutterports having bottom shearing edges; a circular slightly conical impellerhorizontally disposed in said chamber and having an upstanding curvedtooth and an upstanding straight tooth adjacent said cutter liner, saidcurved tooth and said straight tooth having an upper portion and a lowerportion, said upper portions cooperating with said pins and said lowerportions cooperating with said cutter ports to comminute said waste; aradially directed outer peripheral tooth on said impeller, saidperipheral tooth cooperating with said shearing edges to shear saidwaste; drainage means communicating with said chamber; a depending sweepdevice on said impeller to move said waste to said drainage means aftersaid comminution; means for rotating said impeller and a closedcentrifugally actuated circulating oil lubrication system for saidrotating means.

2. A food waste disposer comprising a comminution hopper; means forconnecting said hopper to the drainage outlet of a sink; a hopper cutterliner disposed in said hopper, said cutter liner having radiallyinwardly directed shredding pins, outflow cutter ports and bottom openshearing edges; a circulation impeller horizontally disposed in saidhopper and having an upstanding curved tooth adjacent said hopper liner,said curved tooth having an upper portion and a lower portion, saidupper portion cooperating with said pins and said lower portioncooperating with said cutter ports to comminute said waste; an outerperipheral tooth on said impeller; said peripheral tooth cooperatingwith said shearing edges to shear said waste; drainage meanscommunicating with said hopper; means to move said waste to saiddrainage means after said comminution; and means for rotating saidimpeller.

3. A food waste disposer comprising a comminution hopper; means forconnecting said hopper to the drainage outlet of a sink; a hopper cutterliner disposed in said hopper, said-cutter liner having radiallyinwardly directed shredding pins, outflow cutter ports and bottom openshearing edges; a circulation impeller horizontally disposed in saidhopper and having an upstanding curved tooth adjacent said hopper liner,said curved tooth having an upper portion and a lower portion, saidupper portion cooperating with said pins and said lower portioncooperating with said cutter ports to comminute said waste, said curvedtooth further having a leading rake section and a trailing escapesection, said rake section forming substantially a 20 angle with a linedrawn radially from the center of said impeller to the outer end of saidrake section and said escape section forming substantially a 40 anglewith a line drawn radially from the center of said impeller to the innerend of said escape section; an outer peripheral tooth on said impeller;said peripheral tooth cooperating with said shearing edges to shear saidwaste; drainage means communicating with said hopper; means to move saidwaste to said drainage means after said comminution; and means forrotating said impeller.

4. A cutter tooth rotatable disc-like for a comminuting impeller havinga substantially planar top surface, said tooth extending upwardly fromsaid top surface and having a leading rake section and a trailing escapesection, said tooth configured in a manner whereby a tangent on said topsurface to the end of said rake section forms a 20 angle with a linedrawn radially on said top surface from the center of said impeller tothe outer end of said rake section, and whereby a tangent on said topsurface to the end of said escape section forms a 40 angle with a linedrawn radially on said top surface from the center of said impeller tothe inner end of said escape section.

5. A rotatable disc-like comminuting impeller having a conically formedtop surface, a first cutting member concave in the direction of rotationof said impeller and extending upwardly from said top surface, and asecond non-radial cutting member extending upwardly from said topsurface; said first cutting member having a leading rake section and atrailing escape section, said rake section forming substantially a 20angle with a line drawn radially on said top surface from the center ofsaid impeller to the outer end of said rake section, and said escapesection forming substantially a 40 angle with a line drawn radially onsaid top surface from the center of said impeller to the radially innerend of said escape section.

6. A rotatable disc-like comminuting impeller having a conically formedtop surface, a first cutting member concave in the direction of rotationof said impeller and extending upwardly from said top surface, and asecond non-radial cutting member; said first cutting member having aleading rake section and a trailing escape section, said rake sectionforming substantially a 20 angle with a line drawn radially on said topsurface from the center of said impeller to the radially outer end ofsaid rake section.

7. A rotatable disc-like comminuting impeller having a comically formedtop surface, a first cutting member concave in the direction of rotationof said impeller and extending upwardly from said top surface, and asecond non-radial cutting member; said first cutting member having aleading rake section and a trailing escape section, said escape sectionforming substantially a 40 angle with a line drawn radially from thecenter of said impeller to the radially inner end of said escapesection.

UNITED STATES PATENTS Holland-Letz Dec. 7, Lindenfelser Oct. 211,

Goodall Jan. 30,

Nicholson Jan. 12, Luenberger May 28, Lee Feb. 25, Strehlow May 27,

FOREIGN PATENTS Germany Dec 13,

